1. Technical Field
The present invention relates to a laser light source device provided with a laser light source that emits laser lights, and an illumination device, a monitor device, and a projector provided with the laser light source device.
2. Related Art
The technology of wavelength conversion has been knocks by Second Harmonic Generation (SHG) of generating lights whose wavelength is half of any incoming light. Combining the technology of SHG with the technology of a semiconductor laser can implement laser lights in the visible range of wavelength using an easy-to-get semiconductor laser that oscillates in the far infrared range.
Patent Document 1 (JP-A-5-289136) describes the technology being a result of combination as such. With the technology of Patent Document 1, a ferroelectric material is formed thereon with the periodic structure of polarization inversion so that a wavelength conversion element can be manufactured. In the periodic structure of polarization inversion, a polarization inversion area and a polarization non-inversion area are alternately arranged. In the polarization inversion area, the direction of polarization is uniformly directed in the inverse direction, i.e., direction opposite to the direction of spontaneous polarization observed in a ferroelectric crystal, and in the polarization non-inversion area, the direction of polarization remains directed in the direction of spontaneous polarization.
With the previous technology as such, however, there is a difficulty in forming large (mm unit) the polarization inversion area in the plane direction. The current circumstances allow to align the polarization direction in the range of a few hundred μm in the plane direction but the length of the polarization inversion area in the plane direction is very small. On the other hand, due to the high directivity, the laser lights coming from a laser light source often do not pass through the polarization inversion area even after correctly entering a wavelength conversion element. This results in a failure of not being able to generate second harmonics from the wavelength conversion element with high efficiency, thereby failing in achieving high power.